Two-dimensional (2D) magnetic materials with strong magnetism, long magnetic relaxation times, high temperature ferromagnetism, and large magnetic anisotropy energy (MAE) are promising for applications of nanoscale spintronic devices. Using the spin-orbital coupling density functional theory (DFT) calculations, we investigate the structural stability, electronic structures, and magnetic properties of graphenelike carbon-nitride ($\mathrm{gh}\text{−}{\mathrm{C}}_3{\mathrm{N}}_4$) sheets with the adsorption of whole series of $4f$-block elemental (lanthanide; Ln) atoms. Our results demonstrate that Ln atoms can be stably embedded into/above the center of the cavity of $\mathrm{gh}\text{−}{\mathrm{C}}_3{\mathrm{N}}_4$ monolayer and significantly affect the electronic and magnetic properties. Upon single Ln atom adsorption, all Ln@$\mathrm{gh}\text{−}{\mathrm{C}}_3{\mathrm{N}}_4$ systems show metal character, large spin and orbital magnetic moments, and most of them favor the long-range ferromagnetic ordering. Interestingly, Pr, Nd, Ho adsorbates would possess total magnetic moments of 1.09, 1.47, 6.13 ${\mu }_B$, high Curie temperatures ($T_c$) of 593, 699, 700 K, large MAEs of 4.89, $-17.88$, 21.31 meV/Ln atom, respectively. Based on the electronic structure analyses, we propose that the $4f$ electron hopping between the occupied and unoccupied states around the Fermi level contributes to the large MAE, significant intratomic Ln-$sd$ orbital hybridization with N-$2p$ orbital hybridization gives rise to structural stability, and the coexistence of superexchange and RKKY interactions determines the long-term ferromagnetic coupling between Ln atoms. The present study demonstrates that Ln@$\mathrm{gh}\text{−}{\mathrm{C}}_3{\mathrm{N}}_4$ sheets have significant promise for applications in spintronics such as high density memory devices or for magnetic random access memory.

中文翻译：

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4f块原子原子嵌入gh-C3N4单层：大磁矩，高温铁磁性和巨大的磁各向异性能

具有强磁性，长磁弛豫时间，高温铁磁性和大磁各向异性能（MAE）的二维（2D）磁性材料有望用于纳米级自旋电子器件。使用自旋轨道耦合密度泛函理论（DFT）计算，我们研究了石墨烯状碳氮化物的结构稳定性，电子结构和磁性。$\mathrm{gh}\text{-}{\mathrm{C}}_3{\mathrm{ñ}}_4$）具有整个系列吸附的 $4F$-嵌段元素（镧系元素； Ln）原子。我们的结果表明，Ln原子可以稳定地嵌入/居中于空穴中心。$\mathrm{gh}\text{-}{\mathrm{C}}_3{\mathrm{ñ}}_4$单层并且显着影响电子和磁性。单个Ln原子吸附后，所有Ln @$\mathrm{gh}\text{-}{\mathrm{C}}_3{\mathrm{ñ}}_4$系统表现出金属特性，较大的自旋和轨道磁矩，并且大多数都支持远距离铁磁有序。有趣的是，Pr，Nd，Ho吸附物的总磁矩为1.09、1.47、6.13${\mu }_{乙}$高居里温度（${Ť}_C$）的593，699，700 K，大型MAE为4.89， $-17.88$分别为21.31 meV / Ln原子。基于电子结构分析，我们建议$4F$ 电子在费米能级附近的占据状态和未占据状态之间跳跃是导致较大的MAE的重要原因，而Ln-$sd$ 与N-的轨道杂交$2p$轨道杂交产生结构稳定性，超交换和RKKY相互作用的共存决定了Ln原子之间的长期铁磁耦合。本研究表明，Ln @$\mathrm{gh}\text{-}{\mathrm{C}}_3{\mathrm{ñ}}_4$ 薄板对于自旋电子学中的应用（例如高密度存储设备）或磁性随机存取存储器具有巨大的希望。